Next time you go outside on a clear night, try to estimate how many stars you can see. If you live in Honolulu, you'll probably be able to see only about 20.

From a dark location such as the Big Island you can see 2,000 or more. Pollution from artificial lights is robbing us of our ability to see the night sky.

Residents of Honolulu should ask themselves "When was the last time I saw the Milky Way?" and question whether their children have ever seen this glorious wonder of the night sky. The Milky Way is no longer visible from much of O'ahu.

Poor lighting is to blame for much of the light pollution. Hawai'i is wasting more than $7 million in energy costs each year with lighting that shines directly into space.

House Bill 1835 HD 1, currently being considered by the state Legislature, attempts to make a start at curtailing light pollution by requiring the state Department of Transportation to use fully shielded lighting on all highways and at the airports and harbors.

Fully shielded lights shine light downward only — where it is needed. The lights in common use on our highways are not properly shielded and shine light sideways and upward also. These lights pollute the night sky and create glare.

Glare interferes with our vision at night, and is a particular problem to elderly people, who may be developing cataracts or similar vision problems; our street lights are so poor that they prevent some elderly people from driving at night.

Fully shielded lights on our highways will increase visibility and enhance safety.

Artificial lights are compromising observations from the telescopes on Mauna Kea. Astronaut Ed Lu, a former University of Hawai'i astronomer, took two photographs of Hawai'i at night from the International Space Station. These photographs plainly show that the airports in Hilo, Kona and Kahului and the Hilo harbor are major sources of light.

Much of the lighting at the airports on the Big Island does not comply with the Hawai'i County lighting ordinance, which was designed to protect the night sky over Mauna Kea. The ramp lights at Kahului airport shine directly at the summit of Haleakala. HB 1835 HD 1 will address these problems for the astronomy facilities on Mauna Kea and Haleakala.

Testimony in support of HB 1835 HD 1 has come from the University of Hawai'i and from the Sierra Club. The Department of Transportation has testified in opposition. The DOT stated that the Big Island airport lighting already complies with the Hawai'i County Lighting Ordinance (it does not), and that use of fully shielded street-lights would require all of the light poles to be moved.

In actuality, there are many fully shielded light fixtures that have similar or better photometric qualities to those presently in use — there is absolutely no need to move light poles to use fully shielded lights.

Many of our streetlights are in desperate need of repair. Numerous light fixtures are nearly opaque, with much of the light never making it out of the housing. When these light fixtures are replaced, they should be replaced by fully shielded fixtures.

The lights in use on our highways each consume between $300 and $500 per year in electricity. With such high energy costs, a carefully chosen fixture that directs the light only to where it is needed can save money by allowing a lower-wattage lamp to be used. California has some of the best highway lighting in the United States. California exclusively uses fully shielded fixtures.

House Bill 1835 HD 1 is much more than a bill for astronomers. It will benefit every citizen of Hawai'i, as well at the many visitors who come to Hawai'i.

The improved visibility on our roads will almost certainly save lives. The short-term cost is modest and in the long term, it will save money by reducing energy consumption. New research has linked public health problems, such as breast cancer, to excessive light at night. Many of our homes are no longer dark at night because of trespassing light from the streetlights.

Hawai'i has a strong cultural connection to the night sky — it was discovered by voyagers who used the dark night sky to navigate. It is essential that our senators give this bill a fair hearing. It is time to take back the night.

Richard Wainscoat is an astronomer at the Institute for Astronomy, University of Hawai'i. He wrote this commentary for The Advertiser.